Expression of CD45 and proliferative response to CD3 as suitable classification markers of patients with gastric adenocarcinoma.

25 patients with resectable gastric adenocarcinoma, subdivided according to the absence or presence of residual neoplasic disease (RND- or RND+, respectively), were studied. Cytofluorometric analysis and proliferative responses to mitogens was performed in peripheral blood mononuclear cells of patients. When compared to healthy subjects, the percentage of CD3-expressing cells was significantly reduced in both groups of patients studied (p < 0.0001 in all instances). However, when CD45 is considered instead of (CD3, its expression is found to be significantly reduced only in the RND+ patients (72% +/- 11), when compared with the control group (96 +/- 1%, p < 0.0001). Likewise, cells from these patients significantly less proliferated when stimulated with monoclonal antibodies to CD3 than control cells (18,920 +/- 6,019 cpm vs. 42,697 +/- 1,798 cpm, p = 0.0036); a difference not found if RND- patients (33,619 +/- 11,733 cpm) were considered. We propose that the low expression of CD45 and the poor response to CD3 are markers that are able to identify the subgroup of patients in whom the disease will tend to progress more rapidly. We also suggest the use of such markers as additional criteria for the classification of patients with gastric adenocarcinoma or to identify patients who require more aggressive therapeutic strategies.